The world is still stunned by the deadly plane crash on April 10 that killed the Polish president and other top leaders who were flying from Warsaw to Smolensk in west Russia. As a former airline and military pilot, I want to share some thoughts about the accident.

Firstly, when a pilot is off track or cannot see the runway clearly due to mist, snow or heavy rain during descent, he is allowed to ascend and try the landing again.

As the media has reported, the plane in question was about to land and in fact, it had tried to land four times before it crashed into a tree, which means that it was in good condition and we can dismiss the possibility of sabotage.

Secondly, the pilots and crew members that serve national politicians and state leaders are quite experienced and are licensed with the highest professional standards. So I believe that the pilot and crew members on the plane with the Polish president were experienced and qualified.

Thirdly, any plane must store adequate fuel so that it can fly back to its port of origin or fly to another airport when it encounters problems that deter it from landing at its destination.

So the question is why did the pilot still strive to land though he had received warnings from Russian aviation authorities?

The case is still under investigation, but I think that if the relevant aviation authorities in Russia had been more determined and done something to prevent the plane from landing, the accident would not have happened.

According to the media, the pilot had been "advised" and "warned" not to land and that he should fly to Minsk or Moscow instead for the safety of the plane and the delegation on board.

But instead of "advising" and "warning," why didn't they "order" the pilot not to land, and do something to ban him from landing? In that case, the pilot would have had no other choice than to fly his plane to a safer airport with more favorable weather conditions.

In my opinion, aviation authorities, specifically officials in charge of commanding the air-traffic control tower at airports, should close the runway or absolutely refuse to accept a plane when a landing may be dangerous or risky.

In some urgent cases, necessary commands are a matter of life and death and advice, suggestions or warnings will not work.